The invention relates to a lifting arrangement for a wheel shaft of a vehicle articulated stays for raising the wheel vertically.
Such lifting arrangements of wheel shafts of vehicles are previously known, inter alia, on load-carrying vehicles which incorporate under their load surface two wheel shafts, viz. one driving shaft and one supporting shaft. In an unloaded state the load-carrying vehicle travels mostly with the supporting shaft raised so that the wheels of the driving shaft obtain a good driving grip on the roadway. In a loaded state the supporting shaft is lowered so that the load carried can be distributed over the wheels of both shafts.
Such lifting arrangements incorporate a lifting device, usually in the form of an air bellows arranged between the vehicle""s frame structure and the supporting shaft. The wheel suspension of such a supporting shaft usually incorporates an upper V-shaped reaction stay which extends between the vehicle""s frame structure and the supporting shaft. The V-shaped reaction stay is arranged forward of the shaft and the air bellows is therefore installed on a bracket to the rear of the shaft. As such a vehicle incorporates a multiplicity of components which have to be accommodated or which it is appropriate to install in the vicinity of such a wheel shaft, this location of the air bellows constitutes an obstacle to installing those components. Such a component may be a towing device which makes it possible to attach a trailer vehicle. It is therefore advantageous if the towing device can be installed far forward on the vehicle and preferably in a position immediately to the rear of the rear wheel shaft. This position is also suitable for installing compressed air tanks.
The object of the present invention is to provide a lifting arrangement of the kind mentioned in the introduction for a wheel shaft of a vehicle, which arrangement makes it possible to design and install the lifting device so that it occupies a small space on the vehicle and does not encroach upon the natural or necessary location of other components.
This object is achieved according to the invention by the lifting arrangement mentioned in the introduction which is characterised in that the lifting device is designed to make said lifting possible by displacing the stay device relative to the frame structure. The lifting device will consequently act upon the stay device, and such a technical solution makes it possible to install the lifting device forward of the wheel shaft. The desired space to the rear of the wheel shaft for installing, for example, a towing device or compressed air tanks is thus obtained. Such a lifting device can also be provided with a shorter travel, since this location results in wheel shaft lifting being accomplished with a shorter lever. The result below the lifting device is therefore a space which means that necessary components installed in the vicinity of the wheel shaft, such as control and brake devices, have more space.
According to a preferred embodiment of the invention, the stay device is connected by means of a first fastening element to an upper end of the lifting device. Such a fastening element can be smaller and simpler than a conventional fastening element, since such a conventional fastening element has to extend a relatively long distance between the supporting shaft and the upper end of the lifting device situated to the rear. The fastening element according to the invention may be an integrated part of the stay device and be already fastened to the stay device in the course of manufacture. The frame structure may be connected by means of a second fastening element to a lower end of the lifting device. The lower end of the lifting device is thus provided with stable support and secure fastening to the frame structure. Advantageously, said first and second fastening elements are so oriented that the lifting device has a substantially vertical extent between its upper and lower ends. The lifting device is thus of compact design which occupies a very small space horizontally on the vehicle.
According to a further preferred embodiment of the invention, the stay device comprises two stay elements which form a substantially V-shaped configuration. With such a configuration of the stay device, the first fastening element can extend between the two stay elements and thereby form a stable upper bracket for the lifting device.
The lifting device according to the invention is applicable with advantage on a vehicle which has a frame structure which incorporates two frame side-members extending in the longitudinal direction of the vehicle, whereby each of the stay elements has one end articulatedly connected to its respective frame side-member and a common end articulatedly connected to the wheel shaft. Here it is advantageous that the second fastening element extend between and be connected to said frame side-members, whereby the second fastening element can provide stable support for the lifting device. For said lifting to take place, the lifting device may be designed to be variable in length in order to bring about said displacement of the stay device relative to the frame structure. Such a lifting device may with advantage incorporate an air bellows or a hydraulic cylinder, but other variable-length lifting devices are also conceivable.